Characterization of wind-blown sediment transport with height in a highly mobile dune (SW Spain)

Abstract

The Valdevaqueros dune is located at one of the windiest points of Europe, where the frequent occurrence ofstrong easterly winds has generated a highly mobile dune. Several rotating cup anemometers in vertical array anda self-designed vertical sand trap, were placed to retain the drift sands at different heights over the surface in orderto determine theoretical and actual sand transport rates in the Valdevaqueros dune system. General results showthat 90% of the wind-blown sand is transported within the first 20cm above the dune crest surface. Theoretical transport rates based on different empirical formulae were 0.33 to 0.78 times the in-situ sand transport rate detected,which was 2.08·10^-2kgm^-1s^-1 under moderate wind power (mean speed ranging from 8.4 to 17.9ms^-1). Analysis ofdifferent statistical grain-size parameters helped to understand sand transport distribution at different heights.